1. Field of Invention
Toilet soap bars based upon scap (alkali metal salts of fatty acids) are commonly used for cleansing the human body. While function is important, consumers are also concerned with the appearance of a soap product over its life.
There is a well-known tendency for a bar soap to form cracks after repeated cycles of exposure to moisture and subsequent drying. This tendency is called "wet cracking" (hereinafter "wet cracking" or "cracking") This is in undesirable characteristic as it causes the bar soap to assume an unpleasant appearance that consumers find displeasing.
Wet cracking is a result of several factors. Such factors include product shape, extrusion temperature, sodium chloride content, iodine value on the feed stock, inappropriate mixing during the extrusion process and coconut oil fatty acid content. However, one primary factor that contributes to wet cracking is a high glycerin content. Glycerin is also known in the art as glycerine or glycerol.
It is known that increased cranking will occur as a result of high coconut oil fatty acid (hereinafter "CNOFA") content. The addition of sodium cocoyl isethionate (hereinafter "SCI") will normally increase resistance to cracking in such a soap. However, when a soap bar contains greater than 3 weight percent glycerin, not only does the amount of wet cracking exhibited by the soap bar over its lifetime increase, but the effect of SCI to resist cracking exhibited is virtually loss. Until now, there has not been an effective reduction of wet cracking in a soap bar that contains greater than 3 weight percent glycerin.
2. Description of the Prior Art
Previous attempts have been made to reduce wet cracking. For example, U.S. Pat. No. 5,017.302 to Colwell et al describes the addition of a saturated long chain primary alcohol to reduce cracking.
U.S. Pat. No. 4,265,778 to Sonenstein describes the addition of about 0.1% to 15% of an anionic polymaleic electrolyte will reduce cracking.
U.S. Pat. No. 4,201,528 to Fischer describes a way to reduce cracking in a laminated bar by extruding the soap mass through aligned slots thus eliminating the spiral movement of the soap mass.